How to center a List Element in a Grid Cell with QML?

Hello!
I am new here and developing an UI. I have a List Model with 12 List-Elements which I want to view in a Grid. The result is that the List-Elements are automatically anchored to the upper left conner of the respective Grid-Cell. How can I center each List-Element in its Grid-Cell? Is it possible? I looked through the documentation, but I didn't find anything matching.
Thanx beforehand,
Best regards